ELECTRONIC TROUBLESHOOTING 3176 DIESEL TRUCK ENGINE Caterpillar

Troubleshooting Without A Diagnostic Code

Usage:

NOTE: Before using this section, be sure that you have:

1. Gathered information about the complaint to adequately describe the symptoms.

2. Verified that the complaint is not due to normal engine operation, and,

3. Repaired all ACTIVE Diagnostic Codes.

Then, identify probable causes using the procedure in this section which best describes the symptoms. Then narrow the probable causes using:

* What happened, and when?

* Under what conditions?

* What else occurred?

* When did the symptoms begin (and what else happened at that time)?

* Do they correlate to probable causes?

* Did they occur at the same time as the symptoms?

* Are some logged repeatedly?

* Are they related to this symptom?

* Do they have common probable causes?

Finally, test each probable cause using the tests suggested by the procedure. Be sure to check connectors, especially on intermittent problems!

P-101: Engine Will Not Crank

Probable root causes:

NOTE: These are NOT electronic problems with the 3176 Diesel Truck Engine

* Batteries

* Starting Circuit Problem (in vehicle wiring)

* Starter Solenoid

* Starter Motor

* Starter Ring Gear

* Transmission or Power Take-Off Problem

* Hydraulic Cylinder Lock

* Internal Engine Problem

Perform the following tests in order:

NOTE: For details of the following tests, refer to 3176 Diesel Truck Engine, Form No. SENR4248, for Mechanical Troubleshooting.

1. Charge batteries (see Special Instruction, Form No. SEHS7633, for Battery Test Procedure).

2. Load test batteries (see Operating Manual, Form No. SEHS9249, for Use Of 4C4911 Battery Load Tester.

3. Check vehicle wiring to starter solenoid (see vehicle manufacturers instructions).

4. Inspect starter cables for damage or loose connections.

5. Remove and clean starter cables and connections if corroded.

6. Test starter solenoid operation. Refer to 3176 Diesel Truck Engine, Form No. SENR3909, for Systems Operation Testing and Adjusting.

7. Test starter motor operation. Refer to 3176 Diesel Truck Engine, Form No. SENR3909, for Systems Operation Testing and Adjusting.

8. Remove and inspect starter ring gear for damage.

9. If engine will not turn over by hand, disconnect transmission and check for damage.

10. Check for fluid in cylinders by removing individual nozzles.

11. Disassemble engine to inspect for internal components that may be seized, broken, out of alignment, etc. Refer to 3176 Diesel Truck Engine, Form No. SENR3914, for Disassembly & Assembly.

P-102: Engine Cranks But Will Not Start

Probable root causes:

* Electrical power supply to the ECM.

* Electrical connections to the fuel injectors.

* Fuel supply

* Engine Speed/Timing Signal

* ECM or Personality Module failure.

* Combustion problem

Perform the following tests in order:

1. P-210: Electrical Power Supply Test.

2. If ECAP/DDT does not communicate with ECM, refer to P-120: ECAP/DDT Will Not Communicate With 3176 System, in this manual.

3. Check that Fuel Injector Connector (J5/P5) is installed and oriented correctly.

4. Check Fuel Pressure. Also, check that fuel system is primed and that fuel supply and return lines are not restricted. In temperatures below 0° C (32° F), check for congealed fuel (wax).

5. P-221: Engine Speed/Timing Signal Test. Also be sure the timing reference ring is installed correctly (if the ring was installed backward during reassembly, the engine will not start).

6. Check for combustion problems (too cold or mechanical problem).

P-103: Engine Misfires, Runs Rough Or Is Unstable

NOTE: If the problem is intermittent and cannot be recreated, refer to P-111: Intermittent Low Power Or Power Cutouts.

If the problem is consistent and can be re-created, continue with this procedure.

Probable root causes:

NOTE: If the problem only occurs under certain conditions (high rpm, full load, etc.) test the engine under those conditions. Troubleshooting the symptoms under other conditions can give misleading results.

* Three cylinder cutout

* Individual cylinder malfunction

* Throttle position signal

* Fuel supply

- high pressure- low pressure- air in fuel- poor quality fuel

* Air inlet restriction

* Exhaust restriction

Perform the following tests in order:

1. Verify that the complaint is not about the normal operation of the three-cylinder cutout feature.

2. Isolate misfiring cylinder(s). Refer to P-222: Isolating Misfiring Cylinders, in this manual.

3. Check throttle linkage adjustment. Refer to P-303: Throttle Position Sensor Adjustment, in this manual.

4. Check Throttle Position Sensor. Refer to P-211: Throttle Position Sensor Test, in this manual.

5. Check fuel quality. Refer to the Truck Performance Diagnostic Guide, Form No. SEBD0808

6. Inspect fuel system and check fuel pressure. Refer to 3176 Diesel Truck Engine, Form No. SENR3909, for Systems Operation, Testing & Adjusting.

7. Check for air in fuel. Refer to 3176 Diesel Truck Engine, Form No. SENR4248, for Mechanical Troubleshooting.

8. Check for restrictions in the air inlet and exhaust systems. Refer to 3176 Diesel Truck Engine, Form No. SENR3909, for Systems Operation, Testing & Adjusting.

P-104: Low Power/Poor Or No Response To Throttle

Probable root causes:

* Active diagnostic codes

* Customer Specified Parameters (normal operation)

* Throttle position signal

* Boost pressure signal

* Vehicle speed signal

* Fuel supply

* Air inlet or exhaust restrictions

* Inlet air system leaks

Perform the following tests in order:

1. Troubleshoot any ACTIVE diagnostic codes.

* Codes 31 or 36 limit engine speed to rpm at VSL

* Codes 25 or 42 limit power or rpm or both

* Code 32 limits engine speed to low idle

* Code 56 may limit engine speed to low idle, depending on which parameter caused the code to be generated

2. Verify that complaint is not normal (programmed parameter) operation.

* Check vehicle speed limit, progressive shift parameters etc.

3. Verify that engine has shifted out of Cold Mode

4. P-211: Throttle Position Sensor Test

4. P-225: Boost Pressure Sensor Test

5. P-213: Vehicle Speed Signal Test

6. Inspect fuel system components and check for correct fuel pressure.

7. Check the air inlet and exhaust systems for restrictions, refer to 3176 Diesel Truck Engine, Form SENR4248, Mechanical Troubleshooting.

8. Run PAR (Performance Analysis Report) Test

P-105: Cruise Or PTO Does Not Function

Probable root causes:

* Active Diagnostic Codes

* Customer Specified Parameters (normal operation)

* Cruise/PTO Switches

* Vehicle speed signal

Perform the following tests in order:

1. Troubleshoot any ACTIVE diagnostic codes.

2. Check Customer Specified Parameters

* High Cruise Limit and Low Cruise Limit

* PTO Mode speed limit

3. P-214: Cruise Control and PTO Switches Test

4. P-215: Service Brake and Clutch Switches Test

5. P-213: Vehicle Speed Signal Test

P-110: Intermittent Engine Shutdowns

NOTE: Use this procedure ONLY if the engine has shut down completely and had to be restarted using the key switch.

Probable root causes:

* Battery power or ground to ECM (vehicle wiring).

* Aftermarket engine protection devices [the 2YG (S/N) prefix 3176 Diesel Truck Engine does NOT have its own engine protection shutdown feature].

* 3176 Engine wiring harness

* Fuel supply

* Engine Speed/Timing Sensor

* ECM or Personality Module

Perform the following tests in order:

1. Check external 3176 Harness and connectors (refer to P-201: Inspecting Electrical Connectors.

2. Check for correct installation and operation of engine protection devices.

3. Check for correct installation of J4/P4 (40 Pin-ECM connector).

4. P-210: Electrical Power Supply Test.

5. Check fuel lines for restrictions and fuel tanks for foreign objects which may block fuel supply.

6. P-221: Engine Speed/Timing Sensor Test.

7. P-220: ECM and Personality Module Test.

P-111: Intermittent Low Power Or Power Cutouts

NOTE: Use this procedure only if engine DOES NOT completely shut down (that is, it did NOT need to be restarted using the key switch).

Probable root causes:

* Poor electrical connections

* Battery power or ground to ECM (vehicle wiring)

* Vehicle speed signal

* Engine Speed/Timing Sensor

* Fuel supply

* Throttle Position Sensor

* Cruise control switches

* Service Brake and Clutch Switches

Perform the following tests in order:

1. Check external 3176 Harness and connectors (refer to P-201: Inspecting Electrical Connectors).

2. P-210: Electrical Power Supply Test

3. P-213: Vehicle Speed Signal Test

4. P-221: Engine Speed/Timing Sensor Test

5. Check fuel lines for restrictions and fuel tanks for foreign objects which may block fuel supply.

6. P-211: Throttle Position Sensor Test.

7. P-214: Cruise Control and PTO Switches Test.

8. P-215: Service Brake and Clutch Switches Test

P-112: Intermittent Cruise Or PTO Drop-Out

Probable root causes:

* Poor electrical connection

* Battery power or ground to ECM (vehicle wiring)

* Vehicle Speed Signal

* Cruise control switches

* Service Brake and Clutch Switches

Perform the following tests in order:

1. P-210: Electrical Power Supply Test

2. P-213: Vehicle Speed Signal Test

3. P-214: Cruise Control and PTO Switches Test

4. P-215: Service Brake and Clutch Switches Test

P-120: ECAP/DDT Will Not Communicate With 3176 System

Probable root causes:

* Electrical power supply to ECM

* Connector or wiring problem in 3176 System wiring harness

* ECAP/DDT or service tool "T" Cable problem

* Data Link problem in vehicle system

* ECM or Personality Module

Perform the following tests in order:

1. P-210: Electrical Power Supply Test.

2. P-201: Inspecting Electrical Connectors - Vehicle Connector (J7/P7), Engine Data Link Connector (J8/P8) and ECM Connector (J4/P4).

3. Verify correct operation of ECAP/DDT and Harness Connector Cable on another engine.

4. Disconnect other devices in vehicle using ATA Data Link.

5. P-220: ECM And Personality Module Test.

P-121: ECM Will Not Accept Factory Passwords

Probable root causes:

* Incorrect screen (ECAP expects customer passwords)

* Incorrect Engine Serial Number used to obtain password

* Error entering password

Perform the following tests in order:

1. Verify that ECAP is on factory password screen (and expects Factory Passwords rather than customer Passwords).

2. Verify that engine serial number used to calculate password was from ECAP screen, not from engine information plate.

NOTE: A new ECM comes with the engine serial number programmed as 0XX00000. Be sure to use this number in getting passwords.

3. Verify correct passwords were entered (upper case only). Also check each character in password for accuracy (for instance, I vs. 1, Z vs. 2, etc.).

4. Turn key OFF, then retry.

NOTE: Refer to Factory Passwords section in this manual for more details